The overall objective of this SBIR proposal is the isolation and characterization of previously unidentified gene sequences that may be under transcriptional control by the p53 tumor suppressor. Using a single primer-mediated amplification technology, Targeted Inverted Repeat Amplification (TIRA), we have successfully isolated three such sequences from human and mouse genomic DNA. The immediate objectives of this proposal are to demonstrate that genes linked to these sequences are under the transcriptional regulation of p53. Also, additional putative binding sites will be isolated using TIRA, and evaluated for their potential as p53-mediated elements. The isolation and identification of p53-regulated genes will lead to the development of reagents to be used in characterizing key intermediates involved in cell cycle progression and DNA repair mechanisms. The aberrant regulation of these genes may be significant in many forms of cancer, including breast, ovarian, and prostate. The long-term goals of this research are the in vitro expression of these p53-regulated genes, and the development of specific antibodies against the polypeptide. These antibodies will prove to be extremely useful in designing potential immuno-diagnostic and -prognostic indicators for the detection of these cancers. PROPOSED COMMERCIAL APPLICATION: This research has potential for the development of diagnostic and prognostic immunotherapy reagents. These reagents will also be valuable for determining the cellular pathways in p53-mediated cell responses, and the mechanism of action of the intermediates involved in these pathways.